1. Field of the Invention
The present invention pertains to an improved trigger sprayer apparatus. In particular, the present invention pertains to improvements to a sprayer apparatus of the type comprising a trigger for manipulation by a user of the apparatus to dispense a spray or stream of liquid from the apparatus. The improvements include a venting system employing an elongated slot that allows air to enter a liquid container connected to the apparatus as the apparatus dispenses liquid from the container, a trigger member of the apparatus that provides reliable operation and prevents the inadvertent disconnection of the trigger member from the apparatus, a gasket connected to the apparatus between the liquid container and the apparatus, and a fluid conduit communicating with a nozzle orifice of the apparatus that centers a fluid spinner of the apparatus relative to the orifice.
2. Description of the Related Art
In prior art trigger sprayer apparatus for dispensing liquid from containers, the typical sprayer apparatus is comprised of a sprayer housing having a nozzle for dispensing liquid, a trigger mounted on the housing for pivoting movement relative thereto, a pump chamber formed in the housing, and a pump piston connected to the trigger and received in the pump chamber for reciprocating movement therein in response to pivoting movement of the trigger. The reciprocating movement of the pump piston alternately draws fluid from the container into the pump chamber and then forces the fluid out of the pump chamber and through the nozzle in a spray or stream.
Very often trigger sprayer apparatus of the type described above are manufactured separately from the fluid containers with which they are used. The sprayer apparatus are purchased by suppliers of liquids such as window cleaning liquids, household cleaning liquids, and others, who assemble the sprayer apparatus to their own containers containing their liquids.
In attaching the sprayer apparatus to a liquid container, a gasket is positioned between the sprayer apparatus and container to prevent the liquid from leaking from the connection. The gasket is typically included as a component part of the sprayer apparatus. It has been found in prior art trigger sprayer apparatus that the gasket provided with the apparatus will often become separated from the apparatus and lost in shipment. To overcome this problem, gaskets have been developed that are secured to the sprayer apparatus prior to their shipment. With the gasket secured to the sprayer apparatus, the gasket cannot be separated and lost during shipment.
Some prior art gaskets have been held in position on sprayer apparatus by an insert. Some gaskets are constructed with a layer of metallic foil covered by another layer of a plastic material. The gasket is positioned inside an internally threaded connector of the sprayer apparatus with the plastic and foil layers engaged against the interior of the connector. The foil of the gasket is then heated, causing the plastic layer to melt and adhere the gasket to the connector of the sprayer apparatus.
These types of prior art gaskets are disadvantaged in that the additional processes involved in adding an insert to the apparatus to hold the gasket, or adding foil and plastic layers to the gasket material increase the costs of producing the gaskets. Adding layers of plastic and foil increases the costs of the gasket and requires the additional manufacturing processes of stamping through the foil and plastic layers in forming the gasket. What is needed to overcome these disadvantages of prior art sprayer apparatus gaskets is a gasket that can be attached to the sprayer apparatus in a more economical way than that provided by the prior art.
Trigger mechanisms of prior art sprayer assemblies are typically provided with a pair of laterally spaced flanges at their upper ends that are inserted around opposite lateral sides of a fluid dispensing nozzle attached to the sprayer housing of the apparatus. The flanges are also inserted between extensions of the sprayer housing positioned adjacent the opposite lateral sides of the fluid dispensing nozzle. The flanges are provided with pivot pins on their exterior surfaces that are received in sockets in the extensions of the sprayer housing. The insertion of the pivot pins in the sockets provides a pivoting connection of the trigger member to the sprayer housing.
The trigger members are typically constructed of a resilient plastic that enables the pair of flanges to deform toward each other as they are inserted between the extensions of the sprayer housing. The lateral width of the fluid dispensing nozzle positioned between the flanges is often dimensioned to limit the degree of deflection of the two flanges toward each other, thereby maintaining the pivot pins of the flanges in their pivoting connections in the sockets of the sprayer housing extensions. An example of this type of trigger is disclosed in U.S. Pat. No. 4,153,203. These prior art trigger members and the manner in which they are connected with the sprayer housing have been found to be disadvantaged in that the clearances provided for the trigger flanges between the sprayer nozzle and the extensions of the sprayer housing have limited tolerances. If the clearance is too large, the trigger flanges may flex inwardly toward each other during use and become dislodged from their pivot connections to the sprayer housing extensions, resulting in the trigger member being separated from the sprayer housing. If the clearance is too small, the opposite lateral sides of the sprayer nozzle may engage against the opposed interior surfaces of the trigger member flanges. The resulting friction would resist pivoting movement of the trigger member and could prevent the trigger member from pivoting to its at rest position under the force of its return spring. Hence, the clearance provided in prior art trigger sprayer apparatus between the laterally spaced flanges of the trigger member and the opposite lateral sides of the sprayer nozzle is critical and must be closely monitored during manufacture to prevent the trigger from dislodging from the sprayer housing and to ensure proper pivoting movement of the trigger member without resistance due to friction. What is needed to overcome these disadvantages of prior art sprayer apparatus trigger members is a trigger member having flanges designed to engage around the sprayer nozzle of the apparatus with ample clearance, and designed to be connected to the sprayer housing in a manner that ensures that the trigger member cannot be dislodged from the apparatus during use.
A typical trigger sprayer apparatus is also provided with some system of venting the liquid container connected to the apparatus to allow air to enter the container and occupy the internal volume vacated by liquid dispensed from the container by the sprayer apparatus. One typical venting system employs a resilient diaphragm in the interior of the sprayer housing covering a vent hole that communicates the interior of the container with the container exterior, and a plunger connected to the trigger member of the apparatus. On manipulation of the trigger member, the plunger is inserted through the vent hole and engages the diaphragm, moving the diaphragm away from the vent hole and thereby venting the interior of the container. Examples of this type of venting system are disclosed in U.S. Pat. Nos. 4,153,203; 4,230,277; 4,350,298 and 4,815,663. These prior art venting systems have been found to be disadvantaged in that once the diaphragm has been displaced from its position over the vent hole, the resiliency of the diaphragm material does not enable it to immediately reposition itself over the vent hole once the plunger has been removed. This can result in liquid spilling from the container through the vent hole should the apparatus and connected container be knocked over on one side before the diaphragm is able to return to its original configuration sealing over the vent hole.
Another prior art system of venting the container interior employs a small piston that reciprocates with movement of the trigger member in a tapered cylinder formed in the sprayer housing. The cylinder has a tapered interior bore and the periphery of the piston seats in sealing engagement in the narrow, forward end of the interior bore when the trigger member is moved to its at rest position. The tapered cylinder has a vent hole at its larger, rearward end. The periphery of the piston fits loosely inside the larger end of the cylinder interior bore when the trigger member is pivoted to dispense liquid from the container, thereby enabling a flow of air through the cylinder bore around the periphery of the piston and through the vent hole to the container interior. This prior art system of venting the container interior has been found to be disadvantaged in that a tapered core is necessary to mold the tapered interior bore of the cylinder. Once the cylinder is formed over the core, the core must be removed from the interior of the cylinder through an opening at the narrow end of the tapered cylinder. This often results in splitting of the cylinder at the narrow end as the core is removed. In order to prevent splitting, the sprayer housing molding process must be closely monitored which increases the costs of producing the sprayer housings.
A still further system of venting the container interior again employs a cylinder and a piston connected to the trigger member and received in the cylinder. The cylinder comprises several small ribs formed on and extending axially over its interior surface at a rearward end of the cylinder. The vent hole is also positioned at the rearward end of the cylinder. The ribs engage the periphery of the piston as it is reciprocated through the cylinder in response to pivoting movement of the trigger member. As the piston comes into engagement with the ribs, the ribs separate the periphery of the piston from the interior wall of the cylinder, thereby enabling venting air to flow past the piston to the vent hole communicating with the container interior. An example of this type of venting system is disclosed in Japanese patent No. 52-11686. This prior art system of venting the container interior has been found to be disadvantaged in that the ribs in the cylinder interior deform the resilient material around the periphery of the piston. The resiliency of the piston material does not allow the piston to immediately return to its original configuration. The deformation of the piston periphery prevents the piston from providing a sealing engagement between the periphery of the piston and the interior wall of the cylinder, and allows liquid to flow through the deformation between the piston and the cylinder interior wall should the apparatus and attached container be knocked over on one side.
Prior art sprayer apparatus have also employed venting systems comprised of a cylinder with a piston connected to the trigger member and contained inside the cylinder, where the internal wall of the cylinder is provided with a circular vent hole at an intermediate position in the cylinder. The piston is formed with a pair of spaced annular rings around the circumference of the piston. The rings are separated by an annular groove and straddle the vent hole of the cylinder when the trigger is in the at rest position. Each of the pair of rings engage in a sliding, sealing engagement with the interior of the cylinder. As the piston reciprocates in the cylinder from one side to the other side, the forward most piston ring passes over the vent hole thereby exposing the vent hole to the container exterior and venting the container interior. As the forward piston ring travels back through the cylinder to the opposite side of the vent hole, the vent hole is sealed from the exterior of the container and no fluid can seep past the piston should the apparatus and attached container be knocked over on one side. An example of this type of venting system is disclosed in U.S. Pat. No. 4,072,252. This system of the prior art has been found to be disadvantaged in that, as the piston travels back and forth over the vent hole, the edges of the vent hole formed in the cylinder interior wall produce scratches in the periphery of the forward piston ring and damage its sealing engagement in the interior of the cylinder. These scratches often enable liquid to flow from the container and between the piston ring periphery and the internal wall of the cylinder through the scratches when the apparatus and fluid container are knocked over on one side.
What is needed to overcome all of the above set forth disadvantages of prior art trigger sprayer apparatus venting systems is an improved venting system that enables adequate venting of the container interior during pumping operations performed by the trigger sprayer apparatus by venting the container earlier in the pump piston stroke and for a longer period of the pump piston stroke, while also preventing liquid from leaking from the container through the venting system should the apparatus and connected fluid container be knocked over on one side.
Prior art venting systems of the type discussed above comprising a venting cylinder formed in the sprayer housing of the trigger sprayer apparatus and a reciprocating piston received in the vent cylinder have also been found to be disadvantaged in that the molding of the sprayer housing must be closely monitored to ensure that no imperfections develop in the vent cylinder of the housing. Prior art sprayer housings of this type are typically formed with a fluid conduit to which the sprayer nozzle of the apparatus is attached, a pump cylinder in which the pump piston operated by the trigger member is received, and the vent cylinder in which the vent piston is received. The fluid conduit, pump cylinder and vent cylinder are formed in the sprayer housing with the axes of the conduit, pump cylinder and vent cylinder parallel and coplanar with each other. In molding a sprayer housing of this type from plastic material, extreme care must be taken in order to avoid sinks from forming in the interior surfaces of the pump cylinder and vent cylinder as the molded plastic material of the sprayer housing cools. Very often in sprayer housings of this type, sinks in the form of slight indentations in the interior walls of the pump cylinder and vent cylinder will form as the molded plastic material of the pump cylinder and vent cylinder cools. The sinks produce deformations in the interior surfaces of the pump cylinder and vent cylinder and prevent the pump piston and vent piston peripheries from engaging in a sealing engagement with the pump and vent cylinder interior surfaces. As a result, a trigger sprayer apparatus having a sprayer housing with the sink imperfections formed in the interior surfaces of its pump cylinder and vent cylinder will often leak liquid through the sinks and around the peripheries of the pump piston and vent piston when the apparatus and fluid container are tipped over onto one side. What is needed to overcome this disadvantage of prior art trigger sprayer apparatus is a trigger sprayer apparatus constructed in a manner that prevents sink imperfections from forming in the interior surfaces of the pump cylinder and vent cylinder of the apparatus.
Prior art fluid sprayer apparatus also typically comprise a fluid conducting conduit extending through the sprayer housing that supplies fluid to a nozzle orifice of the apparatus. Fluid pumped by the apparatus through the conduit is dispensed in either a stream or spray from the nozzle orifice. Many prior art trigger sprayer apparatus employ a fluid spinner that imparts a rotation to the fluid as it travels through the conduit prior to its being dispensed from the nozzle orifice. For the fluid spinner to function properly, it must be centered relative to the center axis of the nozzle orifice. Many prior art trigger sprayer apparatus are disadvantaged in that they provide no system of ensuring that the fluid spinner is centered relative to the nozzle orifice.